A few hands on the button.

Hand 1: Feels like a 3-bet, especially with the dead money from the CO. While the $15 raise could be a sizing tell, the tell might not be "I have a monster" but "I have a hand that I want to get HU or win right now."

Hand 2: Meh...less than 70BB effective, lots of players already in, a crappy suited K, and an aggressive BB all seem to make this a fold.

Hand 3: Easy fold.

1) Against a tight guy who is now increasing his raise size, I would probably fold.

2) I kinda think Kxs is crap, so I just fold. But not going to hate too much attempting to take a cheap flyer on the Button either.

3) I default players to a reasonable raising range until they show me otherwise, and against a reasonable raising range I insta-muck ATo without a second thought.

GfoldingmywaytovictoryG

H1 (AQo): absolutely standard squeeze, 100% of the time, mostly due to positions. Not enough info to make a sizing tell.

H2 (K6s): I probably overlimp here on the button with a suited King, but folding is fine. I could see an argument for raising as well but wouldn't myself.

H3 (ATo): turbofold (unless the iso is from CO in which case I could be open to other ideas)

In hand 3 if I had AQo it would be a 3 bet? How about AJo? How about KJs? How about 99's?

Lets say the iso is in the CO.

I just realized I didn't mention the position of the iso in hand three. Lets say he is in the CO.

1. 3bet hu most likely squeeze at max $50-60 because you said he folded to you last time, so I think he will call this just to look you up. Plus I think you need to make it enough to get CO out. If you do indeed get both to call or just HJ and completely miss what's your plan of action?
2.fold
3.fold

1) depends what you mean by "tight". Do you know what range of hands he opens? If it's very tight like only premiums, I would fold. If it's made up of hands like KQo and AT, I would raise.

2) fold.

3) depends on the position of the raiser, and if you think UTG limp/calls you. I'm raising if the original raiser's range is standard, and folding if he's tight and you also think UTG's gonna come along.

Hand 1 3b. In hand 3 AQo would've been a standard 3b, and ATo a fold. I can see AJo going either way, that's the hand I usually have to figure out and tell myself "I can 3b this guy with AJ" or not. If not, fold.
With the hypothetical 99 I think there could be a case for 3b or call. You have the button and will know your hand is usually good if the flop checks to you.

In general I prefer a squeeze situation than an iso as a good 3bet spot, although that may be a bit old fashioned thinking. AQo is good enough to 3bet in both spots. AJo I'd definitely consider a squeeze (although there would be better suited candidates) but it'd still be a fold for me in the H3 situation.

H3 is an easy fold

H2 should also be a fold, but if you are bored and think you'll see a flop enough it's not the most spewy call in the world.

H1 depends a lot on the sizing tell. Would snap 3bet without it, and if I had more than a single piece of info. I could get behind a nit fold. But it can also be JJ/TT that doesn't want callers, or just sizing up because people aren't folding. Calling is the worst option.

Hand 1: HJ needs to be opening 15%+ for me to bother VPIPing here, so it honestly might be a fold. I'm completely indifferent between flatting or 3bing.

Hand 2: The way I form my ranges, I personally raise big here (like $36) as part of my bluff quadrant. Depends a bit on how you form your ranges, but raising all K6s+ would be a mistake, for example.

Hand 3: It is very important for your success as a low stakes live player that this become a very standard fold for you.

Part of why I said ATo needs to be a very easy fold is because of a very important first order assumption/adjustment you need to make for these standard MAWGs raising 5x at 2/3NL games: in the absence of better information, you're best off assuming they have a very static, very passive game with a raise % of 10-15%.

For that reason, I don't care which particular seat between the LJ and CO they happen to be sitting at when they make their raise (especially if it's an ISO); I'm assuming it's tight.

AJo is a closer, but still clearly a -EV flat (whether you 3b it depends on how polar your BTN strat is).

Even AQo is honestly borderline given that assumption, but it's just one of those VPIPs you can very easily justify because of skill edge or gameflow ("I've been here an hour, time to make my first 3b!") or the raiser's dressed snappy or he's got green chips or he's raising one of his first few hands (so Bayesian inference tilts him a bit more aggressive) or UTG made a face when the raise went in or one of the blinds isn't protecting their cards the way they usually do, etc. Maybe you can otherwise make an extremely disciplined fold.

KJs and 99 are clear VPIPs.

All of the hands you listed are pretty indifferent between flatting and 3bing the BTN in theory (with the exception of AJo where any positive expectation you can get out of a 3b is better than the -EV call). Could depend on your reads on the blinds, could depend on gameflow, could depend on your style and preference for hands (eg: you'll want to 3b these hands less if you want to pull hands like AJo out of the muck for a 3b), could just be a straight coinflip. Lots of ways to make money in these games.

Hand 1 - 3B to $75.

Hand 2 - I'm pretty indifferent to all our options here. I'd probably lean towards call, on the BTN. I wouldn't focus on the BB exclusively when there are three blinds to get through, and three players have already VPIP'd in front of us. Odds are if we raise we'll still be going to the flop multi-way. If we don't smash it, we'll hate ourselves for raising pre.

Hand 3 - I probably just call with ATo, when V is new to the table and we have no reads.